Heat-induced immunoreactivity of tau protein in neocortical neurons of fire fatalities

Abstract

Tau protein is the main component of neurofibrillary tangles of Alzheimer's disease (AD). Immunohistochemistry of tau protein is useful in the diagnosis of AD but produces diffuse staining of neocortical neurons in fire fatalities. To learn the cause of this phenomenon, we examined the temporal neocortex of 13 fire fatalities and 9 fatalities unrelated to fire. The diffuse tau immunoreactive neurons were observed in 10 fire fatalities with heat coagulation of the cerebrum. Diffuse staining was not found in the three fire fatalities without heat coagulation of the cerebrum or in fatalities unrelated to fire. The immunoreactivity progressively increased as a function of the degree of cerebral heat coagulation. These results demonstrate that diffuse tau immunoreactivity of neocortical neurons is a post-mortem phenomenon caused by prolonged exposure of the head to intense heat. Forensic pathologists should consider this phenomenon when they diagnose AD in fire fatalities.

Tau protein as a biomarker for asphyxia: A possible forensic tool?

“…Moreover, the involvement of tau in the present study my extend its importance as a biomarker to other brain injury and its related deaths e.g. heat induced brain damage as in the work of Kibayashi and Shojo (2003) . The involvement of tau protein in asphyxial incidents may have great significant implications including: prognostication, therapeutic intervention, and delineating potential treatment windows following such incidents.…”

Expression of heat-shock protein 70 (Hsp70) in the respiratory tract and lungs of fire victims

“…In the forensic literature, the number of studies dealing with heat-shock proteins after burns is also very small [6,25,29,32]. Some authors investigated the heat-induced appearance of other proteins [10,12]. Furthermore, it is not known to what extent data obtained from patients with burn trauma are applicable to the forensic study material.…”

Value of morphological parameters for grading of brain swelling

“…Gross features such as the grooving of the temporal uncus as well as the extension of the cones at the basal part of the cerebellum belong to the generally accepted morphological signs of cerebral edema. However, it has been pointed out that the differentiation from normal anatomical findings may be difficult [7,14,16]. In addition, pathological studies on these cones revealed no correlation between the cone height and the clinically detected state of cerebral pressure [3,15].…”